Air-pump.



L. CLAWSON.

AIR PUMP.

APPucATIoN FILED MAY 12. 1914.

Patented Nov. 30, 1915.

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" Unifrans'rafrns raann'r carica v LEROY cLAwsoN, or HALL, MONTANA, AssIGNon or cnn-HALF 'ro CHARLES i.. cLawsoN, or HALL, MONTANA.

AIR-PUMP.

' Specification of Letters Patent.

Patented Nov. 30, 1915.

f appiicanon me@ :nay iz, 191s. serial No. 838,133.

To all whom t may concern: Be it known that I, LEROY CLAWSON, citizen of the United States, residing at Hall, in the 4,county of Granite and State of Montana, have invented certain new and useful Improvements in Air-Pumps, of which the following is a specification. i This invention relates to air pumps and has special reference to that class of air pumps which are used more particularly for inlating pneumatic tires.

@ne object of the present invention is to provide a pump of compact form, by' the use of which the desired pressure within the tire will be quickly attained, and a further object of the invention is to provide means whereby, if the desired pressure has been attained,any additional air which it may be attempted to force into the tire will be prevented from entering the same and will escape to the atmosphere. The invention also seeks to improve generally the construction and arrangement of the parts of an air pump to the end that the durability and eiiiciency of the same may be increased. The several stated objects and such other objects as will incidentally appear from the following description are attained 1n such a device as is illustrated 'in the accompanying drawings, and the invention consists in certain knovel features which will hereinafter be particularly pointed out in the claims following the detailed description.

In the drawings, Figure 1 is a longitudinal section of an air pump embodying my `present improvements; Fig. 2 is an enlarged section through the stationary piston and the members of the two cylinders immediately adjacent thesame.

In carrying out my invention, I employ a lower cylinder 1, which is rigidly secured to a base 2, and an upper cylinder 3, which is telescopically mounted upon the lower cylinder. form of a stirrup in which the foot of the user may be inserted so as to hold thev pump firmly in its operative position and upon the, upper end or the apex of the stirrup is formed an extensionor plug 4 to which a valve body 5 is rigidly secured, the said valve body being extended above the upper end of the plug 4 so as to receive the lower end of the cylinder 1, and the said lower end of said cylinder being brazed or otherwise rigidly secured in the said valve casing or body. The upper cylinder 3 is,'of course,

The base 2 is preferably in the greater in diameter than the lower cylinder and at its lower end is provided with a cap or head 6 which fits around the iower cylinder so as to slide thereon and is provided with inlet ports 7, as shown. The upper end of the cylinder is also equipped with and closed by a cap or head 8 which may be provided with a handle 9, or may be connected with a motor, so that power may be applied to thev cylinder. Secured in the upper end of the lower cylinder is a sleeve 10 which is expanded laterally above the cylinder so asto rest thereon, as shown at .11, and from the said expanded portion l1,1 the sleeve extends axially within the upper cylinder and is preferably provided with an annular rib or flange 12 at its upper extremity, which is spaced slightly from the inner surface of the said upper cylinder, as shown more clearly in Fig. 2. A flexible piston cup or ring 13 rests upon the upper end of the said sleeve and is formed of leather or similar material, in the usual manner. A plug 14 is secured in'the upper portion of the sleeve 10 and has an annular shoulder 15 which rests upon the inwardly extending portion of the piston cup 13 so as to clamp the same firmly to the ange 12 and the upper end of the sleeve. The plug 14V is centrally bored to provide a socket adapted to receive packing 16pand a compression plug 17 is fitted in the said socket so as to compress the said packing around the piston rod 18. The plug 14 is also provided with one or more longitudinal passages 19 which are expanded at their lower ends to permit the flow of air from the upper cylinder to the lower cylinder and contain check valves which, in the present instance, are illustrated-as consisting of balls 20 adapted to seat against the internal annular shoulders 21 and held normally against said seats by springs 22 fitted within the lower expanded portions of the air passages. Retaining plugs 23 are secured in the lower portions of the said passages so as to prevent escape of the springs and the balls, and also to permit regulation of the tension of the springs iii an obvious manner. The said retaining plugs are bored axially at 24 tifs to permit the air to escape from the air readily understood. The upper end of the said piston rod is aixed rigidly to the upper cap or head 8 so that the rod will move with the upper cylinder, and upon the lower en d of the said rod I secure a piston whlch 1s arranged to operate in the lower cylinder. The lower extremity of the piston rod is threaded, as shown at 25, and locking and adjusting nuts 26 and 27 are mounted upon the said threaded extremity. Below and against the upper nut 26 is tted a disk or washer 28, and between the said washer and a smaller washer 29 which rests against the lower nut 27 I provide the packing or piston cup 30 which 1s ofthe'usual construction and formed of leather or similar material.v The piston cups 13 and 30 operate in the usual manner'so that upon theV intake stroke the-annular members of the cups will yield to the pressure of the air so as to permit the air to flow between the piston cup and the wall of the cylinder while, on the compression or force stroke of the pump, the

annular members of the piston cups will fit tightly against the wall of the cylinder and prevent escape of the air.

The plug 4 upon the top of the base or stirrup 2 is Jformed with'a valve seat 31 in its upper end and also with a longitudinal chamber 32 opening through its lower` end. A valve 33 is arranged to engage the seat 3l and the said valve is provided with a stem 34 which ,extends longitudinally through the chamber 32 and around said stem between the head 35 and the upper end of the chamber 32 is coiled a spring 36 which is normally expanded so as to hold the stem in its lowest position with the Valve 33 upon its Seat 31, thereby preventing escape of the compressed air through the plug. The lower end of the head 35 1s constructed with radial grooves 37 which may be engaged by a screw driver or similar tool inserted through an opening 38 in the base of the stirrup 2 so as to adjust the valve stem and place the spring 36 under the desired tension. A nut 39 is mounted upon the upper extremity of the stem above the valve 33 s0 as to secure the valve in position to seat properly according to the tension placed upon the s ring 36. The valve stem is also provided w1th a longitudinal passage 40 opening through its lower end and having its upper end opening laterally through the stem immediately below the valve 33. In the normal position of the parts, the upper end of this vent passage is covered by the upper portion of the plug directly to the atmosphere. The cylinder 1 is provided at its lower end with a lateral escape port 41 which is in direct alinement with a port 42 in the valve casing 5, and the said port 42 forms the inner end of a passage or chamber 43 in the said casing. A check valve is mounted in the said chamber orpassage 43 to permit flow therethrough from the pump'and to prevent theow in the reverse dlrection.

While any desired `form of check valve may be employed, I prefer to use a valve of the same character as those shown in the stationary piston hereinbefore described. In the drawing, 44 indicates the ball or valve member, 45 the spring holding the said ball or valve toits seat and 46 the bored plug secured in the end of the chamber or passage 43 and receiving the thrust of the spring 45. The passage 43 communicates directly with the interior of a supplemental relief cylinder 47 which is'formed integral with or secured rigidly to the valve casing 5 and is disposed. parallel with the cylinder 1. The said supplemental cylinder is equi ped with a nipple 48 upon which may be tted one end of a hose 49 which is engaged upon the inflation valve of the tire in the usual manner and as will be readily understood. The lower end of the cylinder 47 is open, while the upper end is closed by apap-or head 50, as shown. Within the lower portion of the said cylinder is fitted a piston 51 having a lug or extension ,52 at its lower end, to which is loosely and pivotally attached one end of a relief lever 53, said lever being fulcrumed upon the stirrup 2, as shown at 54, and having its free end bearing against the lower end of the head 35. The piston 51 is equipped with packing rings 55 so as to prevent leakage around the piston and its upper end is adapted to seat against an internal annular shoulder 56 in the cylinder 47 below the passage or chamber 43. The upper end of the said piston is equipped with a hook or equivalent device 57 which is engaged by and holds the lower end of a pressure controlling or governor spring' 58, the said spring extending axially within the upper portion of the cylinder and having' its upper end secured about a swivel plug 59, the said plug 59 being swiveled upon the lower'end of an adjusting' screw or bolt 60 which is mounted in and extends through the cap 50, and a nut or gland 61 is fitted around the bolt -or screw 60 to bear upon the said cap and compress the packing 62 thereagainst to prevent leakage around the adjusting screw or bolt. By rotating the said screw or bolt so that the stem will move longitudinally in the cap 50, the spring 58 will be put under more or less tension and, consequently, may be regulated so as to withstand more or less pressure from the air within the hose 49, the chamber 43 and the cylinder 47. l

It is thought the operation and advantages of my improved pump will be readily understood from the foregoing description taken in connection with the accompanying drawings. The spring 58 is adjusted in the described manner so as to resist expansion under any degree of pressure up to that upper cylinder above the -from its seat air may escape which it is desired to attain in the tire. The

wardly over the lower cylinder the piston connected therewith will, of course, move toward the bottom of the lower cylinder, and any air which may be below said piston will be driven through the ports 41 and 42 into the chamber 43 and thence iow through the hose 49 into thc tire. During the downward movement of these parts air wiil, of course, low in through' the port 7 in the lower end ofthe upper cylinder, and any air which may be in thel upper portion of the upper cylinder will be compressed against the upper stationary piston and will overcome the tension of the springs so as to open the check valves in said piston and thence escape into the lower cylinder. On the up stroke the air in the lower portion of said cylinder. will also be created in the stationary piston, and the pressure of the atmosphere will be suiiicient to. cause air to flow into the upper cylinder past the piston cup or packing 13 and be caught in the upper cylinder. Upon 'the next down stroke of the pump this air will, oi course. be forced through the stationary piston into the space below the same and will eventiuvl'lv be forcedl from the lower cylinder through the valve casing 5 into the tire in the manner previously described. The pressure in the tire will, of course, be the same as the Ipressure in the hose 49 and 'the cylinder il", and when this pressure has reached a degree when it will overcome the tension o'l the spring 58 it will act upon the 'ci .on 5l in opposition to said spring so as ko niove the piston outwardly or downwardly and thereby v'brate the lever 53 so that the i'ree end of said lever will lift the valve stem 8l against the tension of the spring 36 and, consequently, raise the valve 3B rom its seat 31 so that the air then in the cylinder will escape from the vent passage all. The notches or grooves 37 in the lower caught in the A partial vacuum end of the head 35 will permit said air to "dow around the lever 53 and thereby avoid choking of the vent. The operator will be made aware at once of the fact that air is no longer passing into the tire, as he will hear the hissing caused by the escape of air from the vent and will also find the pump immediately working more easily than when the air is being forced into the tire. The packing rings 55 may be removed Jfrom the piston 51 so that when the piston moves around the piston and the pressure in the cylinder be thereby relieved, but l prefer to use the packing rings for the reason that premature lower cylinder will flow past the piston cup 30 and be release lof the pressure and reduction of the same in the tire is thereby avoided. It will be readily noted that my improved air pump y is very compact in the arrangement of its parts and it will be `found highly efficient in use inasmuch as the air `is gradually compressed in the successive stages of'its flow through the stationary piston and the stationary cylinder, and when the operation of the pump ceases there will be a partially compressed supply of air trapped between the lower movable piston and the check-valves iny theupper stationary piston. The-valve casing 5 not only forms a support for the check valve which governs the escape of the air to the tire and the supplemental or pressure governing cylinder', but also serves as a s top to limit the ldesired movement of the upper cylinder and, consequently, prevents injury to the workingparts which might be caused sive stroke to the upper cylinder.

Having thus described my invention, what I claim is:

'1. An air pump comprising a compression cylinder, a piston working therein, a valve casing secured upon the said cylinder and having an outlet passage leading from the said cylinder, a governor cylinder carried by said casing and communicating with the said outlet passage, a check valve in the passage in said casing, a relief valve in the end of the compression'cylinder, a piston in the governor cylinder, operative connections between the said piston and the relief valve, a spring disposed within the governor cylinder to normally hold the piston inactive, and means for regulating the tension of said spring.

2. 2in air pump comprising a compression cylinder, a piston working therein, a plug closing the lower end oi said cylinder, a valve seating upon the said plug `and having a stem extending therethrough, said stem being provided with a vent passage, means for holding said valve normally seated whereby the vent passage will be closed by the plug, and means controlled by the pressure of the air discharged from the compression cylinder or unseating said valve whereby to open said vent.

3. n air pump comprising a compression cylinder, a piston working therein,'a plug closing the end of the cylinder and axially bored, a valve seating upon the said plug and having a stem extending through the plug, said stem being provided with a vent passage, the upper end of which is normally closed by the plug, a spring housed within the plug and holding the valve normally seated whereby said vent passage will be closed, a lever bearing upon the stem in opposition to the said spring, and means controlled by the air discharged from the compression cylinder to vibrate said lever and by any tendency to impart an excesand a lever pivotally connected tosaid piston and in constant operative engagement with the relief valve.

5.v n air p ump comprising a compression cylinder, .a plston working thereln, a govnection with the said sprlng.

n air pump comprising a compression cylinder, a relief valve in the end of the sure from the compression cylinder, means for yieldably sure, and a lever mounted between the transversely lsite end holding the piston against the said presgovernor cylinder and the relief valve and having one end pivotally connected tothe piston and its opposite end bearing against the grooved end of the relief valve.

7. An air pump consisting of a comp sion cylinder, a bored lower end of said cylinder, a valve seatin in the upper'fend of the bore of said plug and having a stem extending through said bore and provided with an enlarged head at its lower end, said stem having a vent lpassage opening through its lower end and laterally near its upper end, and the upper end of said inder carried by said valve casing and in com' munication therewith and having an open lower end, a piston slidably mounted in the governor cylinder and filling and projecting through the open lower end of the same, and a lever fulcrumed between the said' piston and the relief valve and having one end pivotally connected to the piston and its oppobearing against the enlarged head at the lower end of the stem of the relief valve.

u In testimony whereof I aflix my signature V1n presence of two witnesses.

LEROY CLAWSON.

YL. s.] 

